std::distance
From cppreference.com
Defined in header
<iterator>
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template< class InputIt >
typename std::iterator_traits<InputIt>::difference_type |
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Returns the number of elements between first
and last
.
The behavior is undefined if last
is not reachable from first
by (possibly repeatedly) incrementing first
.
Contents |
[edit] Parameters
first | - | iterator pointing to the first element |
last | - | iterator pointing to the end of the range |
Type requirements | ||
-
InputIt must meet the requirements of InputIterator . The operation is more efficient if InputIt additionally meets the requirements of RandomAccessIterator
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[edit] Return value
The number of elements between first
and last
.
[edit] Complexity
Linear.
However, if InputIt
additionally meets the requirements of RandomAccessIterator
, complexity is constant.
[edit] Example
Run this code
#include <iostream> #include <iterator> #include <vector> int main() { std::vector<int> v{ 3, 1, 4 }; auto distance = std::distance(v.begin(), v.end()); std::cout << distance << '\n'; }
Output:
3
[edit] See also
advances an iterator by given distance (function) |